1. Field of the Invention
The invention relates to video-graphics controllers and in particular to a single-chip controller for the simultaneous display of color image data on two display devices having inconsistent refresh requirements, such as interlaced TV and color DSTN LCD.
2. Background of the Invention
Portable computers (e.g., laptops, notebooks, etc.) are becoming more powerful and are currently being used for multimedia video-graphics presentations in which a color image is displayed simultaneously on a CRT monitor or color television receiver, such as an NTSC projector, and on the computer's own flat-panel color display. During a presentation, it is common for the CRT or TV to display color images while the portable's flat-panel display is used to display the speaker's notes or presentation outline.
At the present time, no single-chip video-graphics controller can handle such diverse display needs because the refresh rates for the CRT/TV and for the flat-panel display are not compatible. A current solution to the problem is to use two different controllers, each specialized for the particular display device it must control. Such an arrangement is both expensive and power consuming since both controllers operate all the time.
What is needed is a controller architecture which incorporates both display functions into a single chip, and which accommodates a wide variety of display types by appropriate internal programming while aggressively conserving operating power.